Future focus of research
The plan is to focus on improving the chemical selectivity of the cold plasma hydrocarbon reforming. Specifically, for reforming tar compounds, it is established that DBD plasma along with the catalysts can achieve up to 95% destruction efficiency with the specific energy of 7.1 kWhr/Nm3. This specific energy is very high. Future research through modelling and experimentation will address this limitation. The effort will be to improve chemical selectivity by controlling gas dynamics/reactor design, to reduce the specific energy values to < 0.1 kWhr/Nm3. This work will provide a solution for the tar issues of the gasification process.
Plasma activated water
PAW has many fundamental questions still not answered such as: what determines the chemistry of PAW? and how to selectively generate/control the desired water chemistry? The research direction is to understand the interactions/relations between the cold plasma operating parameters such as plasma volume, electrode configuration, operating current, and electron temperature with the plasma chemistry in the headspace. The approach to answer this is to carefully map all the 900+ chemical reactions involving 33 species and mathematical modelling of the system. The plan is to establish a relation between the species generated around the plasma to that of the PAW. To be specific, it is understood that ~ 50 ppm levels of H2O2 along with the ~ 20 ppb level of per-oxynitrate contributes to the antimicrobial nature of the PAW. However, how to achieve only these species in PAW by suppressing other chemistry is yet to be understood. Designing plasma systems to prepare PAW with high species selectivity and yield will revolutionize the application of PAW for specific applications such as cancer treatment, burn wounds and treatment of multidrug-resistant bacteria. For this work, the plan is to continue working with established collaborations both inside and outside IISc namely the Department of Microbiology and Cell Biology and M/s Sri Shankara Research Centre, Rangadore Memorial Hospital. This work will open a new field of plasma medicine.
Plasma activated water as a source of green fertilizer
To use PAW as an alternative green fertilizer, the specific energy consumption from its current value of 900 MJ/kg of N, should be reduced to the loss incorporated Haber-Bosch process value of 260 MJ/kg of N. The current specific energy consumption value is two orders of magnitude higher than the theoretical limit of 7 MJ/kg of N. Research will focus to bring down this specific energy by increasing the chemical selectivity of the PAW process. The work will bring down the CHG emissions from fossil fuel-based fertilizers and establish decentralizing the fertilizer generation process.
Utilization of MSW
In addition to these cold plasma-based research plans is to continue the research efforts onto new areas such as MSW gasification. Building on my experience with biomass gasification, I plan to work on the utilization of MSW to produce value-added products – energy, bio-hydrogen, liquid fuels and compost using thermochemical and biological conversion processes. The focus would be on the fundamental work addressing challenges of solid, liquid and gaseous emissions, and demonstration. This research is expected to solve the growing MSW handling issues of the country.